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Espresso Machine Types
Under Pressure: Comparing Different Types
of Espresso Machines
Introduction
There are several types of electric home espresso machines on the
market, and they can be divided into three kinds: the electric steam, the
electric piston, and the electric pump/boiler. The last kind, the
electric pump/boiler, will, for the purpose of this article, be further split into
three categories: semi-automatic, automatic, and super-automatic.
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Electric Steam
This type was the first kind espresso machine that ever received any
real popularity in the American mainstream. Here's how it works: water that
has been poured into a reservoir is heated to boiling. This same
pressurized water is used both to steam milk and brew the espresso. This method
gets the water pressure up to about 1 bar (although, the preferred pressure at
which espresso is brewed is about 8 bar).
Many folks like using an electric steam
espresso machine in order to brew a coffee just a bit stronger than drip
coffee. However, given
the advent of the next type of machine, boiler machines are now of out
of step with mainstream espresso connoisseurs. |
Advantages
- These machines
are relatively inexpensive; machines
can start at $30.00.
- The units usually include
a carafe
for espresso collection.
- They feature simple to use electronics;
usually these machines incorporate just a few switches and a dial.
- Not an
espresso fan, but want strong coffee? This unit can do
that.
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Disadvantages
- Only very low pressure can be
achieved, which makes the production of crema unlikely. The
espresso made from these units is widely considered to be
sub-par.
- Water reservoir takes several
minutes to heat up and usually does not hold much water.
- Most have a plastic
exterior.
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Electric Piston
The electric piston type espresso machine, produced by companies
such as La Pavoni, is very classy looking
and can actually be a lot of fun to use. Although some folks are
so enamored by their aesthetic appeal that they put them up for shelf
display, they are actually capable of producing a pressure of 8-9
bar, the benchmark pressure of a genuine espresso drink. Like the
steam boiler model, the water reservoir heats up to the appropriate
temperature for both milk frothing and steaming. Just open the steam valve and let the
foaming begin.
The pressure for brewing espresso is
achieved by pulling on a hand lever which is attached to a piston.
Pulling the piston up brings water into the group, and pushing it down
forces hot water through the grounds in the portafilter. |
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Advantages
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The
user has precise control over pressure
applied.
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Often a thermometer is included so that you know when your water is
at optimal temperature.
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The
porta-filter is
usually heavy-duty, like the
machine's hull.
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Disadvantages
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Not just any ape can figure these
out (this ape, for instance, needed a bit of time to learn how to operate one of these
machines expertly).
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Some units can be quite loud during
initial heating up.
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The
reservoir is one big boiler, so the unit can often take quite some
time to heat up (several minutes).
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Since steaming water is maintained in the boiler, the water may be
considered by some to be too hot for brewing.
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Pump
The pump machine has made
things much easier for espresso lovers. Electric steam machines
didn't make enough crema, but electric piston machines could get a
little unwieldy.
The pump machine uses a
pump that
pulls water from a reservoir and returns it into a tank that heats the
water. Two separate thermostats control brew temperature and frothing
temperature. After the boiler heats the water to brewing temperature
and the brew button is pressed, the pump activates and water gets pushed
through the boiler, then through the grounds in the brew head.
In order to froth milk, the steam
button is pressed and the unit also heats the water in the boiler, but
to a hotter temperature than brewing temperature. Since brewing
and steaming occur at different temperatures, sometimes multiple heating
systems are used so that the user doesn't have to wait between brewing
and steaming. After steam is
produced, a valve can be opened, releasing some of the steam through the
wand.
The first pump machines operated with a
boiler. The boiler, however, can take up to ten minutes to heat
up. The next series of pump machines included a heating system
which could heat the water in a matter of minutes. Today's pump machines
usually take between fifty to ninety seconds to
heat up, and many use super-fast heating systems called thermal blocks
or thermal coils. Others still use small boilers.
Traditionalists and
espresso "purists" prefer the quality of espresso produced by a boiler
machine than that produced by a thermal coil or block. However,
for the average consumer, the difference in flavor is nearly
undetectable. |
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Semi-Automatic
The semi-automatic pump machine is one of the most popular home
espresso machines available. It is called semi-automatic
because after flipping a switch, the pump does the work that the
hand used to in the electric piston machines. The pump will
continue pumping water through to the brew head. Flipping the switch again will make the pump
stop pumping water. |
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Automatic
The automatic pump machine is very similar to the
semi-automatic, with the following distinction. In the case of
the semi-automatic, a button is pushed once to start the pump for
brewing, once to stop the pump for brewing. In the case of the
automatic, however, a button is pressed to activate the pump and the
machine will stop after a preset amount of time. |
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Super
Automatic
The super automatic pump machine, perfected by Jura-Capresso and
Saeco, is the same as the automatic
except it has the added feature of grinding the coffee beans (unless,
as is possible with certain super automatics,
powder is deposited directly into the unit), disposing of the
grounds, and even cleaning, rinsing, and descaling
itself. The super automatics often have many other added
features like strength settings, temperature settings, digital
displays, coffee powder quantity settings, water amount settings,
grind size selections, and
others. |
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Advantages
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There is much less user error
with these push button-based machines compared to electric piston
machines.
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The super automatic pump
machines are less messy than others.
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Proper pressure is always
achieved in quality pump machines, which means simple brewing and
usually easy frothing.
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Convenience is the
key with these units.
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Disadvantages
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Like
some owners of manual
transmission automobiles, there are those who prefer the control of
electric piston machines or semi-automatics to automatics or super
automatics.
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Most automatics and
super automatics have a plastic hull, which is less sturdy and
more easily damaged than metal machines.
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Super automatic
machines are often very pricy, starting at $400.00 and extending
into the several thousands.
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